تعیین مقاومت بتن مسلح به وسیله مقاومت ظاهری بسته به شرایط پخت Determination of the reinforced concrete strength by apparent resistivity depending on the curing conditions

1. INTRODUCTION Non-destructive geophysical methods are effectively used for reducing the damage of concrete and to obtain economic results in terms of time and financial. With these methods, it is possible to detect the faults of the materials during manufacturing or after a certain period of use (cracks due to corrosion or abrasion, voids in the internal structure, reinforcement detection, etc.). Some researches has also been used several methods combined. The problems related to the structure have increased the importance of structure analysis. Some of the main important targets of the structural analyzing investigations by using non-destructive geophysical techniques such as electrical resistivity technique (ERT) is used for determine the electrical properties of concrete and reinforcement corrosion (Feliu et. al., 1996; Lataste et. al., 2002; Polder and Peelen, 2002; Güneyisi et. al., 2005; Ferreira and Jalali, 2006; Sadowski, 2010; Plooy et. al., 2013; Ghosh and Tran, 2015); induced polarization (IP) is used for obtaining information about concrete sample structure (Altundaş, 2010); electromagnetic (EM) is used for determination presence of reinforcement (Zhao et. al., 2014; Moustafa et. al., 2016); ground-penetrating radar (GPR) is used for display of reinforcement fittings in columns and beams, determination of existing building foundation type and discontinuity investigations in columns and beams (Buyle-Bodin et. al., 2003; Sbartai et. al., 2007; Cassidy et. al., 2011); seismic ultrasonic wave technique is used for determine the quality of concrete, internal cracks as well as the deterioration in the concrete and estimation of the concrete strength (Pimenov et. al. 1972; Martin and Forde, 1995; Yeih and Huang, 1998; Naffa et. al., 2002; Kewalramani and Gupta 2006; Lorenzi et. al. 2007; Trtnik et. al., 2009; Uyanık et. al., 2011; Uyanık, 2012; Uyanık and Tezcan, 2012; Uyanık et. al., 2012); Petro and Kim, 2012; Pfister et. al., 2014; Sabbağ and Uyanık, (2016a; 2017)); Schmidt Hammer is used for determining concrete strength (Ergün and Kürklü, 2005; Jain et. al., 2013); microtremor is used for determining the foundation type (Uyanık, (2014; 2015); Uyanık et. al., 2015), dynamic behavior of building (Navarro and Oliveira, 2008), construction period (Timur et. al., 2015) and seismic effects on building structure (Sanches et. al., 2002); radioactivity (RA) is used for the effects of construction materials radioactivity quantities on human health (Uyanık et. al., 2013; Kılınçarslan et. al., 2011; Abbasi, 2013; Akkurt et. al., 2013; Işık et. al., 2017). From among them the impact of reinforcement and curing conditions to the concrete strength can be determined by measuring resistivity of concrete. In this case, valuable data can be obtained without any damage to the structure so as to deal with problems such as the concrete strength of the existing structure and the status of the reinforcement in the concrete.